Use this video tutorial to learn how to dry tomatoes and store them in olive oil, including information on safety to store them at room temperature.
Drying tomatoes and storing them in olive oil remains one of my favorite preservation techniques. They are so full of flavor and are ready to be added to salads, appetizers (like this Goat Cheese Appetizer) or any recipe without rehydrating first. Plus, when the tomatoes are gone, the oil makes a super tomato-flavored base to salad dressings or tomato sauces.
I originally wrote a tutorial for how to dry and store tomatoes in olive oil that pictured all the steps a couple years ago, but because of reader questions about what the tomatoes should look like and a reader's suggestion (thanks, Sakura!) Brian and I put together a 5 minute video that outlines each step and also goes into detail about what the tomatoes should look like when dry enough to store in oil.
How to Dry and Store Tomatoes in Olive Oil Video
I hope this video makes it clearer for you and that you'll see how easy it is to make and store tomatoes this way. It's just another awesome way to put up our garden (or market) produce for the winter!
Here's more on the safety of this technique that I mentioned in the video:
I've stored dried tomatoes in olive oil, unrefrigerated, since the 1990's after reading about it in The Oregonian and being sure of it's safety (it's from cooking author Jan Roberts-Dominquez and I found that original tutorial reprinted here). Last year, however, I read on a popular gardening blog that it "wasn't considered safe anymore." Sigh.
I did a fair amount of research at that time - even contacting Ms. Roberts-Dominquez who originally wrote about this technique in her newspaper column (linked in the newer article above) - and updated my original tutorial with the information I found.
The safety research included these highlights (please read the original post for more details):
- This is a time-honored preservation technique that I feel good about for two reasons: tomatoes are naturally acidic (and I never add any fresh garlic or herbs), and I dry them until they are pliable, but no liquid comes from them when I test them with my fingers. I also, as per Ms. Dominguez’s recommendation, dip them in red wine vinegar to help extend their shelf life (and just so happens to increase the acidity).
- The recommendation that storing tomatoes this way is no longer safe was not backed by any studies and I wasn’t able to find any other site or research to back up this claim.
- The reasoning didn't make sense: potential for water droplets to contain botulism - in dried tomatoes that exude no moisture when touched? Or oil affecting the lid gaskets when the oil doesn't touch the lid?
- A book on preserving followed up on this as well and found that the idea that botulism will occur in dried tomatoes seems to be an internet phenomenon with no science backing up the claim.
To my other research about the safety of this time-honored preservation technique and to make sure that you are able to make an informed decision, I'm adding this recommendation from Colorado State University Extension:
Dried tomatoes in oil are less of a safety concern than other mixtures in oil because the pH of tomatoes is generally 4.6 or lower. In addition, by sufficiently drying the tomatoes, conditions become even less favorable to growth of C. botulinum due to a decrease in water activity. Dried herbs in oil also are less of a safety concern because of their low water activity. However, to ensure safety, it is recommended that all tomato in oil and herb in oil products be stored at refrigerator temperatures and used within three days.
Since I do store my tomatoes at room temperature, I don't agree with all that they state though I do agree with the "dried tomatoes are less of a safety concern" part.
Continuing to dry and store tomatoes in olive oil at room temperature doesn't mean that I'm going to ignore all USDA preserving safety information and start canning in my oven or turning over my jars to "seal" them - or even stop putting citric acid in my canned tomatoes. I DO want to be as safe as possible.
But I look at the jars of dried tomatoes stored in olive oil on my shelves that have always been perfectly safe and I think about some of the things passing as food on shelves in supermarkets that the government has deemed "safe"...
I think I'll stick to my tomatoes, thank you.